- Run a game with research pending.
- Sweep out a red area for demolish.
- Leave red area active without actually deleting anything, and wait for research to finish.
- After you dismiss the research completed pop up, the red area will not delete anything, nor can it be dismissed.
Trying to save and re-load doesn’t help, as the red delete zone is persistent in the save file. You can only restore from a save game prior to the problem.